As copper-based sintered slide members (bearings), there are known Cu—Sn-solid lubricant-based sintered slide members containing a solid lubricant such as graphite and lead. Also, in order to improve the load carrying capacity thereof, there are known multi-layer sintered slide members constructed of a metal backing plate such as a steel plate and a sintered layer made of the above sintered material which is integrally formed on the surface of the metal backing plate. For example, there has been proposed the multi-layer copper-based sintered slide member having an integral multilayer structure constructed from a copper-based alloy sintered layer and a steel-based metal backing plate in which the copper-based alloy sintered layer is composed of 1 to 11% by weight of tin, 1 to 30% by weight of lead, 0.5 to 5% by weight of spherical carbon and the balance essentially consisting of copper (Patent Document 1).
Lead as a solid lubricant is an important component of the conventional copper-based sintered slide members as a material capable of allowing the slide members to exhibit an excellent conformability with a counterpart member when subjected to sliding motion thereon, and enhancing an anti-seizing property thereof. However, in recent years, the use of lead must be avoided from the viewpoints of environmental problems, etc.
Patent Document 1: Japanese Patent Application Laid-Open (KOKAI) No. 7-138681